Three-dimensional characterization of the active volumes of PTW microDiamond, microSilicon, and Diode E dosimetry detectors using a proton microbeam.

Daniela Poppinga,Ulrich Giesen,Björn Delfs,Ann‐Britt Ulrichs,Björn Poppe,Hui Khee Looe,Rafael Kranzer,Frank Langner

doi:10.1002/mp.13705

Daniela Poppinga, Ulrich Giesen + Show 6 more

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https://doi.org/10.1002/mp.13705

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Abstract

PurposeThe purpose of this work is the three‐dimensional characterization of the active volumes of commercial solid‐state dosimetry detectors. Detailed knowledge of the dimensions of the detector’s active volume as well as the detector housing is of particular interest for small‐field photon dosimetry. As shown in previous publications from different groups, the design of the detector housing influences the detector signal for small photon fields. Therefore, detailed knowledge of the active volume dimension and the surrounding materials form the basis for accurate Monte Carlo simulations of the detector.MethodsA 10 MeV proton beam focused by the microbeam system of the Physikalisch‐Technische Bundesanstalt was used to measure two‐dimensional response maps of a synthetic diamond detector (microDiamond, type 60019, PTW Freiburg) and two silicon detectors (microSilicon, type 60023, PTW Freiburg and Diode E, type 60017, PTW Freiburg). In addition, the thickness of the active volume of the new microSilicon was measured using the method developed in a previous study.ResultsThe analysis of the response maps leads to active area of 1.18 mm2 for the Diode E, 1.75 mm2 for the microSilicon, and 3.91 mm2 for the microDiamond detector. The thickness of the active volume of the microSilicon detector was determined to be (17.8 ± 2) µm.ConclusionsThis study provides detailed geometrical data of the dosimetric active volume of three different solid‐state detector types.

Highlights

In our previous work,[1] we have established the use of a highly focused proton radiation provided by the microbeam system of the Physikalisch-Technische Bundesanstalt (PTB) for the characterization of detector’s active volume
Based on a previous work, the aim of this study is to extend the proton microbeam technique to obtain two-dimensional response maps of radiation detectors and to allow the complete characterization of the active volumes
For the Diode E 60017 detector, an active area of (1.18 Æ 0.10) mm[2] was measured, which corresponds to a diameter of (1.22 Æ 0.05) mm

Summary

Introduction

In our previous work,[1] we have established the use of a highly focused proton radiation provided by the microbeam system of the Physikalisch-Technische Bundesanstalt (PTB) for the characterization of detector’s active volume. The diameters and thicknesses of the active volumes of several commercial solid-state detectors for dosimetry in radiation therapy have been determined. For the determination of correction factors based on Monte Carlo simulations,[8,9,10] the dimension of the active volume must be precisely known in order to enable correct modeling of the detector’s design. Based on a previous work, the aim of this study is to extend the proton microbeam technique to obtain two-dimensional response maps of radiation detectors and to allow the complete characterization of the active volumes

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